4J43

The coefficient of thermal expansion of 4J43 alloy is lower than that of soft glass, and its conductivity is also poor. After copper plating, its radial coefficient of thermal expansion can be made substantially consistent with that of soft glass, while significantly improving its conductivity and thermal conductivity.

Category：

Nickel-iron alloy series

Keywords：High resistance electric heating alloy | Corrosion-resistant alloy | Thermal spraying materials

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4J43

Product Overview

4J43 expansion alloy has a certain expansion coefficient from 20℃ to 400℃ and is specifically used as copper-clad Fe-Ni alloy wire, commonly known as Dumet wire.

The expansion coefficient of 4J43 alloy is lower than that of soft glass, and its conductivity is also poor. After copper cladding, its radial expansion coefficient can be basically consistent with that of soft glass, while greatly improving its conductivity and thermal conductivity.

A layer of borate, which is close to the composition of glass, is applied over the copper layer. When sealing with soft glass, it will have good wettability. The alloy has good mechanical strength and corrosion resistance, and has good resistance to most acids and alkalis, but it is more sensitive to strong oxidants and strong acids such as nitric acid.

Implementation Standard: YBT5236-2005

Good Wettability

A layer of borate, which is close to the composition of glass, is applied over the copper layer. When sealing with soft glass, it will have good wettability.

Good Mechanical Strength

The alloy has good mechanical strength and corrosion resistance.

Corrosion Resistance

The alloy has good mechanical strength and corrosion resistance.

Application Areas

Suitable for precision measuring instruments, optical instruments, precision machinery instruments, etc., and is also often used in the manufacture of precision electronic components such as magnetic sensors, inductors, magnetic cores, and magnetic heads.

Chemical Composition

Alloy	%	C	P	S	Si	Mn	Ni	Fe
4J43	Minimum					0.75	41.0	Balance
4J43	Maximum	0.10	0.02	0.02	0.30	1.25	43.0	Balance

Physical and Mechanical Properties

Density	Melting Point Range (°C)	Average Linear Expansion Coefficient (20°C-400°C)	Resistivity Ω·mm²/m
8.22 g/cm³	1435°C	6.3-7.2	0.11

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4J47